(lē'və-rō'tə-tôr'ē, -tōr'ē) also le·vo·ro·ta·ry (-tə-rē) adj. (Symboll-) Of or relating to an optically active chemical that rotates the plane of polarized light to the left, or counterclockwise: Only levorotatory amino acids are biologically active.
symbol: ( — )- or (formerly) l-; describing a chemical compound that rotates the plane of polarization of a transmitted beam of plane-polarized light or other electromagnetic radiation to the left, i.e. in an anticlockwise direction as viewed by the observer looking towards the light source.
describing any leftwards or anticlockwise rotation. Compare dextrorotatory.